spi: rspi: Use SPI core DMA mapping framework
authorGeert Uytterhoeven <geert+renesas@glider.be>
Mon, 2 Jun 2014 13:38:12 +0000 (15:38 +0200)
committerMark Brown <broonie@linaro.org>
Mon, 2 Jun 2014 14:49:34 +0000 (15:49 +0100)
Use the SPI core DMA mapping framework instead of our own.
If available, DMA is used for transfers larger than the FIFO size
(8 or 32 bytes).

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
drivers/spi/spi-rspi.c

index 7b993f75a3cf380646f378cbc411a5515d522b16..753ac7bdfd559fc6c3e5aaac7a515eef7f80f7a2 100644 (file)
@@ -195,10 +195,6 @@ struct rspi_data {
        int rx_irq, tx_irq;
        const struct spi_ops *ops;
 
-       /* for dmaengine */
-       struct dma_chan *chan_tx;
-       struct dma_chan *chan_rx;
-
        unsigned dma_callbacked:1;
        unsigned byte_access:1;
 };
@@ -251,6 +247,7 @@ struct spi_ops {
                            struct spi_transfer *xfer);
        u16 mode_bits;
        u16 flags;
+       u16 fifo_size;
 };
 
 /*
@@ -466,39 +463,16 @@ static void rspi_dma_complete(void *arg)
        wake_up_interruptible(&rspi->wait);
 }
 
-static int rspi_dma_map_sg(struct scatterlist *sg, const void *buf,
-                          unsigned len, struct dma_chan *chan,
-                          enum dma_transfer_direction dir)
-{
-       sg_init_table(sg, 1);
-       sg_set_buf(sg, buf, len);
-       sg_dma_len(sg) = len;
-       return dma_map_sg(chan->device->dev, sg, 1, dir);
-}
-
-static void rspi_dma_unmap_sg(struct scatterlist *sg, struct dma_chan *chan,
-                             enum dma_transfer_direction dir)
-{
-       dma_unmap_sg(chan->device->dev, sg, 1, dir);
-}
-
 static int rspi_send_dma(struct rspi_data *rspi, struct spi_transfer *t)
 {
-       struct scatterlist sg;
-       const void *buf = t->tx_buf;
        struct dma_async_tx_descriptor *desc;
-       unsigned int len = t->len;
-       int ret = 0;
-
-       if (!rspi_dma_map_sg(&sg, buf, len, rspi->chan_tx, DMA_TO_DEVICE))
-               return -EFAULT;
+       int ret;
 
-       desc = dmaengine_prep_slave_sg(rspi->chan_tx, &sg, 1, DMA_TO_DEVICE,
+       desc = dmaengine_prep_slave_sg(rspi->master->dma_tx, t->tx_sg.sgl,
+                                      t->tx_sg.nents, DMA_TO_DEVICE,
                                       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
-       if (!desc) {
-               ret = -EIO;
-               goto end;
-       }
+       if (!desc)
+               return -EIO;
 
        /*
         * DMAC needs SPTIE, but if SPTIE is set, this IRQ routine will be
@@ -513,7 +487,7 @@ static int rspi_send_dma(struct rspi_data *rspi, struct spi_transfer *t)
        desc->callback = rspi_dma_complete;
        desc->callback_param = rspi;
        dmaengine_submit(desc);
-       dma_async_issue_pending(rspi->chan_tx);
+       dma_async_issue_pending(rspi->master->dma_tx);
 
        ret = wait_event_interruptible_timeout(rspi->wait,
                                               rspi->dma_callbacked, HZ);
@@ -524,9 +498,6 @@ static int rspi_send_dma(struct rspi_data *rspi, struct spi_transfer *t)
        rspi_disable_irq(rspi, SPCR_SPTIE);
 
        enable_irq(rspi->tx_irq);
-
-end:
-       rspi_dma_unmap_sg(&sg, rspi->chan_tx, DMA_TO_DEVICE);
        return ret;
 }
 
@@ -562,39 +533,22 @@ static void qspi_receive_init(const struct rspi_data *rspi)
 
 static int rspi_send_receive_dma(struct rspi_data *rspi, struct spi_transfer *t)
 {
-       struct scatterlist sg_rx, sg_tx;
-       const void *tx_buf = t->tx_buf;
-       void *rx_buf = t->rx_buf;
        struct dma_async_tx_descriptor *desc_tx, *desc_rx;
-       unsigned int len = t->len;
-       int ret = 0;
+       int ret;
 
        /* prepare transmit transfer */
-       if (!rspi_dma_map_sg(&sg_tx, tx_buf, len, rspi->chan_tx,
-                            DMA_TO_DEVICE))
-               return -EFAULT;
-
-       desc_tx = dmaengine_prep_slave_sg(rspi->chan_tx, &sg_tx, 1,
-                       DMA_TO_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
-       if (!desc_tx) {
-               ret = -EIO;
-               goto end_tx_mapped;
-       }
+       desc_tx = dmaengine_prep_slave_sg(rspi->master->dma_tx, t->tx_sg.sgl,
+                                         t->tx_sg.nents, DMA_TO_DEVICE,
+                                         DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+       if (!desc_tx)
+               return -EIO;
 
        /* prepare receive transfer */
-       if (!rspi_dma_map_sg(&sg_rx, rx_buf, len, rspi->chan_rx,
-                            DMA_FROM_DEVICE)) {
-               ret = -EFAULT;
-               goto end_tx_mapped;
-
-       }
-       desc_rx = dmaengine_prep_slave_sg(rspi->chan_rx, &sg_rx, 1,
-                                         DMA_FROM_DEVICE,
+       desc_rx = dmaengine_prep_slave_sg(rspi->master->dma_rx, t->rx_sg.sgl,
+                                         t->rx_sg.nents, DMA_FROM_DEVICE,
                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
-       if (!desc_rx) {
-               ret = -EIO;
-               goto end;
-       }
+       if (!desc_rx)
+               return -EIO;
 
        rspi_receive_init(rspi);
 
@@ -613,11 +567,11 @@ static int rspi_send_receive_dma(struct rspi_data *rspi, struct spi_transfer *t)
        desc_rx->callback = rspi_dma_complete;
        desc_rx->callback_param = rspi;
        dmaengine_submit(desc_rx);
-       dma_async_issue_pending(rspi->chan_rx);
+       dma_async_issue_pending(rspi->master->dma_rx);
 
        desc_tx->callback = NULL;       /* No callback */
        dmaengine_submit(desc_tx);
-       dma_async_issue_pending(rspi->chan_tx);
+       dma_async_issue_pending(rspi->master->dma_tx);
 
        ret = wait_event_interruptible_timeout(rspi->wait,
                                               rspi->dma_callbacked, HZ);
@@ -631,19 +585,21 @@ static int rspi_send_receive_dma(struct rspi_data *rspi, struct spi_transfer *t)
        if (rspi->rx_irq != rspi->tx_irq)
                enable_irq(rspi->rx_irq);
 
-end:
-       rspi_dma_unmap_sg(&sg_rx, rspi->chan_rx, DMA_FROM_DEVICE);
-end_tx_mapped:
-       rspi_dma_unmap_sg(&sg_tx, rspi->chan_tx, DMA_TO_DEVICE);
        return ret;
 }
 
-static int rspi_is_dma(const struct rspi_data *rspi, struct spi_transfer *t)
+static bool __rspi_can_dma(const struct rspi_data *rspi,
+                          const struct spi_transfer *xfer)
 {
-       if (rspi->chan_tx)
-               return 1;
+       return xfer->len > rspi->ops->fifo_size;
+}
 
-       return 0;
+static bool rspi_can_dma(struct spi_master *master, struct spi_device *spi,
+                        struct spi_transfer *xfer)
+{
+       struct rspi_data *rspi = spi_master_get_devdata(master);
+
+       return __rspi_can_dma(rspi, xfer);
 }
 
 static int rspi_transfer_out_in(struct rspi_data *rspi,
@@ -676,7 +632,7 @@ static int rspi_transfer_one(struct spi_master *master, struct spi_device *spi,
 {
        struct rspi_data *rspi = spi_master_get_devdata(master);
 
-       if (!rspi_is_dma(rspi, xfer))
+       if (!master->can_dma || !__rspi_can_dma(rspi, xfer))
                return rspi_transfer_out_in(rspi, xfer);
 
        if (xfer->rx_buf)
@@ -976,7 +932,7 @@ static struct dma_chan *rspi_request_dma_chan(struct device *dev,
        return chan;
 }
 
-static int rspi_request_dma(struct device *dev, struct rspi_data *rspi,
+static int rspi_request_dma(struct device *dev, struct spi_master *master,
                            const struct resource *res)
 {
        const struct rspi_plat_data *rspi_pd = dev_get_platdata(dev);
@@ -984,31 +940,32 @@ static int rspi_request_dma(struct device *dev, struct rspi_data *rspi,
        if (!rspi_pd || !rspi_pd->dma_rx_id || !rspi_pd->dma_tx_id)
                return 0;       /* The driver assumes no error. */
 
-       rspi->chan_rx = rspi_request_dma_chan(dev, DMA_DEV_TO_MEM,
-                                             rspi_pd->dma_rx_id,
-                                             res->start + RSPI_SPDR);
-       if (!rspi->chan_rx)
+       master->dma_rx = rspi_request_dma_chan(dev, DMA_DEV_TO_MEM,
+                                              rspi_pd->dma_rx_id,
+                                              res->start + RSPI_SPDR);
+       if (!master->dma_rx)
                return -ENODEV;
 
-       rspi->chan_tx = rspi_request_dma_chan(dev, DMA_MEM_TO_DEV,
-                                             rspi_pd->dma_tx_id,
-                                             res->start + RSPI_SPDR);
-       if (!rspi->chan_tx) {
-               dma_release_channel(rspi->chan_rx);
-               rspi->chan_rx = NULL;
+       master->dma_tx = rspi_request_dma_chan(dev, DMA_MEM_TO_DEV,
+                                              rspi_pd->dma_tx_id,
+                                              res->start + RSPI_SPDR);
+       if (!master->dma_tx) {
+               dma_release_channel(master->dma_rx);
+               master->dma_rx = NULL;
                return -ENODEV;
        }
 
+       master->can_dma = rspi_can_dma;
        dev_info(dev, "DMA available");
        return 0;
 }
 
 static void rspi_release_dma(struct rspi_data *rspi)
 {
-       if (rspi->chan_tx)
-               dma_release_channel(rspi->chan_tx);
-       if (rspi->chan_rx)
-               dma_release_channel(rspi->chan_rx);
+       if (rspi->master->dma_tx)
+               dma_release_channel(rspi->master->dma_tx);
+       if (rspi->master->dma_rx)
+               dma_release_channel(rspi->master->dma_rx);
 }
 
 static int rspi_remove(struct platform_device *pdev)
@@ -1026,6 +983,7 @@ static const struct spi_ops rspi_ops = {
        .transfer_one =         rspi_transfer_one,
        .mode_bits =            SPI_CPHA | SPI_CPOL | SPI_LOOP,
        .flags =                SPI_MASTER_MUST_TX,
+       .fifo_size =            8,
 };
 
 static const struct spi_ops rspi_rz_ops = {
@@ -1033,6 +991,7 @@ static const struct spi_ops rspi_rz_ops = {
        .transfer_one =         rspi_rz_transfer_one,
        .mode_bits =            SPI_CPHA | SPI_CPOL | SPI_LOOP,
        .flags =                SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX,
+       .fifo_size =            8,      /* 8 for TX, 32 for RX */
 };
 
 static const struct spi_ops qspi_ops = {
@@ -1042,6 +1001,7 @@ static const struct spi_ops qspi_ops = {
                                SPI_TX_DUAL | SPI_TX_QUAD |
                                SPI_RX_DUAL | SPI_RX_QUAD,
        .flags =                SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX,
+       .fifo_size =            32,
 };
 
 #ifdef CONFIG_OF
@@ -1199,7 +1159,7 @@ static int rspi_probe(struct platform_device *pdev)
                goto error2;
        }
 
-       ret = rspi_request_dma(&pdev->dev, rspi, res);
+       ret = rspi_request_dma(&pdev->dev, master, res);
        if (ret < 0)
                dev_warn(&pdev->dev, "DMA not available, using PIO\n");